TW201600734A - Oil diffusion pump and oil vapor generator used therefor - Google Patents

Abstract

Provided is an oil diffusion pump provided with an oil vapor generator capable of eliminating a problem that arises when a heater wire is used as a hydraulic oil heating source. The oil diffusion pump is a vacuum pump in which an oil vapor generator (70) is disposed in a casing (51) and operated, thereby evaporating a hydraulic oil (8) into oil vapor, and the oil vapor is ejected from jets (53, 53a) to discharge an intake gas. The oil vapor generator (70) is provided with a tubular case (71) (object to be heated) that extends in an upright direction, an induction coil (75) wound around the tubular member (71) through an insulating material (73), and a feeding means for applying an alternating current to the induction coil (75). The case (71) and the induction coil (75) are build in the casing in such an arrangement as to be immersed in the hydraulic oil (8) stored in the casing (51). The feeding means is operated to apply the alternating current to the induction coil (75), thereby heating the case (71) itself and thus evaporating the hydraulic oil (8).

Description

Oil diffusion pump and oil vapor generator using the same

The present invention relates to an oil diffusion pump and an oil vapor generator incorporated in the pump, the oil diffusion pump being connected to a vacuum container of various vacuum devices constituting a vapor deposition device, a sputtering device, and the like, and is suitable for It is utilized as a vacuum pump for the purpose of evacuating the inside of the container.

In various vacuum apparatuses such as a vapor deposition apparatus and a sputtering apparatus, an oil diffusion pump is used as a vacuum pump used for evacuating the inside of a vacuum vessel constituting the apparatus. In the conventional oil diffusion pump, an electrothermal heater including a heating wire is used as a heating source of the working oil contained in the boiler (Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-23778

In the case where the heating wire is used as the heating source of the working oil, there is an advantage that the device can be formed at a low cost, but the heating function is lost due to, for example, the heating wire is broken, and the electric leakage due to the insulation of the heating wire is generated. The high temperature causes poor contact, and the rust caused by the heated body causes defects. The main reason. Moreover, since the heating line becomes high temperature and is hot when the oil diffusion pump is actuated, it is necessary to pay attention to the installation place, and the degree of freedom of the mounting position is limited depending on the place where the radiant heat from the heating line is considered. Set the environment for the problem.

Further, since the heating wire serving as the heating source of the working oil also causes heat conduction loss in terms of energy efficiency, there are the following problems in addition to low heating efficiency and power saving.

(1) The rise in heating is slow (long startup time), (2) thermal response is poor, and (3) it is difficult to selectively heat the object to be heated, and the periphery of the object to be heated is also heated.

According to an aspect of the present invention, an oil vapor generator capable of solving the problem when a heating wire is used as a working oil heating source, and an oil diffusion pump including the oil vapor generator capable of contributing to power saving when operating are provided.

In the oil diffusion pump of the present invention, an oil vapor generator is disposed in an injector disposed in a casing, and the oil vapor generator is operated to heat the working oil to become oil vapor, and the oil in the injector is used. A vacuum pump that injects steam from an ejector to perform a high vacuum exhaust operation of the suction gas.

The oil vapor generator includes: a heated body; an induction coil that is electrically insulated from being disposed in the vicinity of the object to be heated; and a power feeding device that applies an alternating current to the induction coil. Then, it is characterized in that an alternating current is applied to the induction coil by actuating the power feeding device, so that the object to be heated itself is heated and the working oil is vaporized.

The oil vapor generator of the present invention is used in a housing to be included And the working oil in the oil diffusion pump of the ejector is heated to be used as oil vapor. The oil vapor generator of the present invention includes: a heated body, which is disposed in an ejector in a casing so that a part or all of the working oil is immersed in a casing of the oil diffusion pump; the induction coil, The electric power is applied to the induction coil in such a manner that a part or all of the working oil is immersed in the casing so as to be electrically insulated. Then, it is characterized in that the heating target is heated and the working oil is vaporized by actuating the power feeding device.

In the above two inventions, the shape of the object to be heated constituting the oil vapor generator is not particularly limited, and for example, a plate shape, a cylindrical shape, a combination of a plate shape and a cylindrical shape, or the like can be considered. For example, when the object to be heated is formed in a tubular shape extending in the upright direction (Figs. 3 to 5), the induction coil is wound around the object to be heated by the insulating material (Fig. 3) ~ Figure 5). In the case where the object to be heated is formed of a plate material such as a disk shape, the induction coil may be disposed around the object to be heated (for example, the back surface or the like) through the insulating material. In the case of combination, in addition to a plurality of power feeding devices using separate induction coils, a system of induction coils and power feeding devices can be used to supply power. In any case, the object to be heated and the induction coil in the present invention are housed in the casing in such a manner that part or all of the oil to be immersed in the casing is disposed.

In the present invention, a flow path of the working oil that can be heated by the oil vapor generator can be provided in the casing of the oil diffusion pump.

In the present invention, the oil vapor generator disposed in the casing can be thermally insulated from the bottom surface of the casing.

In the present invention, an insulated and heat-resistant electric wire structure can be used. The induction coil of the oil vapor generator.

The oil vapor generator incorporated in the oil diffusion pump of the present invention is used as a working oil heating source, and is configured by arranging an induction coil through an insulating material in the vicinity of the object to be heated (as an example, in a cylindrical heating body) The induction coil is wound around the insulating material, and the heating element is heated by applying an alternating current to the induction coil, and the working oil is vaporized by the heat. Further, the object to be heated and the induction coil are placed in the bottom of the casing with the arrangement of the hydraulic oil immersed in the casing of the oil diffusion pump.

That is, when the oil vapor generator incorporated in the oil diffusion pump of the present invention is used, the induction coil is not heated, but an alternating current is applied to the induction coil in a specific direction of the object to be heated (in the case of the above-described example) The body refers to the magnetic flux that generates the interlinkage in the upright direction, and the generated magnetic flux causes the heated body to generate an induced current, that is, an eddy current is generated, thereby generating Joule heat (induction heating). The heated body itself is heated by the heat generated thereby (heating itself by the heated body), thereby heating the working oil.

As a result, since there is no member that consumes the heating wire, the heat generation function does not occur due to the disconnection. Moreover, since all the electric current is consumed by the object to be heated as the heating element, electric leakage does not occur due to insulation failure, and the terminal block does not cause contact failure due to high temperature. Further, since the nature of the working oil heating source can be locally heated, there is also an advantage that the degree of freedom in the arrangement of the induction coils is increased.

Further, when the oil vapor generator incorporated in the oil diffusion pump of the present invention is used, the heated body and the induction coil are partially or completely immersed in The arrangement of the working oil accumulated in the casing of the oil diffusion pump is loaded. As a result, even when the temperature of the induction coil rises due to the temperature rise of the object to be heated, the cooling effect obtained by the hydraulic oil can be expected, and abnormal heating can be prevented. Therefore, the upper limit temperature of the induction coil can be suppressed to be lower than, for example, a mode in which the induction coil is disposed outside the casing and air is cooled.

Since the oil diffusion pump of the present invention incorporates the oil vapor generator of the present invention into the casing, all the electric current applied to the induction coil of the oil vapor generator can be consumed in the object to be heated as the heating element. As a result, the energy efficiency of the heating element is good and power saving can be achieved.

By providing a flow path for the hydraulic oil heated by the oil vapor generator in the casing of the oil diffusion pump, it is not necessary to provide a pipe for the working oil circulation on the atmospheric side (the same as the casing, the same applies hereinafter) on the bottom of the casing. As a flow path of the working oil, the housing can be simplified.

By the working oil passing through the flow path heated by the object to be heated, it is expected that it is initially heated in the flow path in the middle of the working oil circulation, and a state suitable for generating oil vapor can be created.

In the oil diffusion pump of the present invention, as described above, an oil vapor generator as a heating source is disposed in the casing, and a heating source is not provided outside the casing of the heating source included in the conventional oil diffusion pump. Therefore, the bottom of the casing can be roughly flattened, and the oil diffusion pump can be placed horizontally, and the convenience can be improved.

Further, according to an example of the oil vapor generator of the present invention, since the object to be heated which is a heating element is wound around the induction coil, the upper end of the straight cube is exposed above the oil surface contacting the working oil, so that the oil is exposed from the oil surface. The rising oil vapor is connected to the upper part of the heated inner wall exposed above the oil level. The touch is thereby further heated and the oil vapor that has been sufficiently heated can be generated in a short time. As a result, the oil diffusion pump in which the oil vapor generator is incorporated can heat and raise the working oil in a shorter period of time (that is, generate oil vapor), and is very advantageous from the viewpoint of energy efficiency.

1‧‧‧Vacuum device

8‧‧‧Working oil

10‧‧‧Vacuum container

21, 23, 25~29‧‧‧ pipeline

31‧‧‧Main valve

33‧‧‧Leak valve

35‧‧‧Roughing valve

37‧‧‧Auxiliary valve

39‧‧‧Leak valve

50‧‧‧oil diffusion pump

51‧‧‧Shell

53‧‧‧Injector

53a‧‧‧Jet nozzle

55‧‧‧Inhalation Department

57‧‧‧Exhaust Department

58‧‧‧Water cooling tube

59‧‧‧ oil tank

60‧‧‧ rough pump

70‧‧‧Oil vapour generator

70a‧‧‧Rack

70b‧‧‧foot

71‧‧‧Box (an example of a heated body)

71a‧‧‧Inside area

71b‧‧‧Outer area

72‧‧‧Base

72a‧‧‧ openings

73‧‧‧Insulation materials

75‧‧‧Induction coil

76‧‧‧Magnetic shielding box

90‧‧‧Under cover (flange)

92‧‧‧fasteners

Fig. 1 is a schematic block diagram showing a vacuum apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing an oil diffusion pump used as an example of the vacuum apparatus of Fig. 1.

Fig. 3 is a schematic cross-sectional view showing a main part of an oil vapor generator used as an example of the oil diffusion pump of Fig. 2.

Fig. 4 is a schematic plan view of Fig. 3 viewed from the IV direction.

Fig. 5 is a view showing another example of the main part of the oil vapor generator corresponding to Fig. 3.

Fig. 6 is a view showing another example of the configuration of the oil vapor generator charged to the oil diffusion pump of the present example.

Fig. 7 is a view showing another example of the configuration of the oil vapor generator charged to the oil diffusion pump of the present example.

Hereinafter, an example of the present invention will be described based on the drawings.

As shown in Fig. 1, the vacuum apparatus 1 of the present example has a vacuum vessel 10. In the inside of the vacuum chamber 10, a film formation source (not shown) such as an evaporation source or a sputtering source, and a substrate holder for holding a substrate to be processed are disposed. Various equipment necessary for forming a film (film formation). The vacuum vessel 10 is connected to the downstream side of the line 21. The vacuum vessel 10 is connected to a vacuum gauge (not shown) to detect the air pressure (vacuum degree) in the vacuum vessel 10.

The upstream side of the line 21 is connected to the downstream side of the suction line 23 through the main pumping valve 31. The upstream side of the suction line 23 is connected to the suction portion 55 of the oil diffusion pump 50. The downstream of the line 21 is connected to the downstream side of the branch line 25. The intermediate portion of the branch line 25 is connected to the downstream side of the line 26, and the upstream side of the line 26 is provided with a leak valve 33.

The upstream side of the branch line 25 is connected to the downstream side of the line 27 through the rough valve 35. The upstream side of the line 27 is connected to the rough pump 60. The middle of the line 27 is connected to the downstream side of the line 28. The upstream side of the line 28 is connected to the exhaust portion 57 of the oil diffusion pump 50 through the auxiliary valve 37. The connection portion of the line 28 of the line 27 is connected to the downstream side of the line 29, and the upstream side of the line 29 is provided with a leak valve 39. The inside of the line 28 is connected to a vacuum gauge (not shown) to detect the pressure in the oil diffusion pump 50.

The vacuum apparatus 1 of the present example includes a control device (not shown) that controls the operation of the apparatus 1 in addition to the above configuration. The control device included in the present example is configured to include a main control circuit (not shown), various processing circuits, a vacuum gauge drive circuit (not shown), and a vacuum connected to the inside of the line 21. The rough pump control circuit (not shown) is an operation control rough pump 60; and an oil diffusion pump control circuit (not shown) is an operation control oil diffusion pump 50.

The main control circuit is connected to each valve (main pumping valve 31, leak valve 33, 39, roughing valve 35, auxiliary valve 37), and these valves are in accordance with the main control circuit. Opened and closed in a specific order. The oil diffusion pump 50 is connected to the rough pump 60, and the gas that is exhausted by the oil diffusion pump 50 through the auxiliary valve 37 is sucked by the rough pump 60 and discharged from a path (not shown).

As shown in Fig. 2, the oil diffusion pump 50 of the present example has a cylindrical container (housing) 51 whose bottom is closed. The bottom portion of the casing 51 is filled with an oil vapor generator 70 that heats the working oil 8 to be vaporized, and the bottom portion of the casing 51 is set to be substantially flat. Details of the oil vapor generator 70 will be described later. An ejector 53 is disposed in the casing 51. Here, the hydraulic oil that has been heated by the oil vapor generator 70 (see FIG. 3) is vaporized and the oil vapor that has risen is introduced, and is passed through the nozzle 53a. Spray it in the direction of rough drawing. The upper end of the casing 51 is provided with an intake portion 55, and the side surface of the casing 51 is provided with an exhaust portion 57.

Next, the operation of the oil diffusion pump 50 will be described.

When the main steam pump 70 is opened and the oil vapor generator 70 is actuated, the hydraulic oil 8 is heated to the vicinity of the boiling point by the oil vapor generator 70, and is vaporized by the oil to fill the injector 53. Further, it is ejected from the nozzle 53a to the inner surface of the side wall of the casing 51. The suction gas (the air in the vacuum vessel 10) sucked from the intake unit 55 by the injection is blown in the direction in which the jet flow progresses, and is exhausted by the exhaust portion 57. Thereby, evacuation in the vacuum vessel 10 can be performed. The "circle (○)" in Fig. 2 schematically shows the state of the oil vapor after the oil is vaporized. Moreover, the suction portion 55 is opened after the oil vapor is ejected from the ejector nozzle 53a so that the hydraulic oil 8 does not enter the vacuum container 10.

Further, since the casing 51 is cooled by the water cooling pipe 58, the oil vapor of the working oil 8 adhering to the inner wall of the casing 51 is cooled and condensed and returned to the oil groove 59 below the casing 51, and by the oil vapor. Generator 70 is added again It is hot and vaporized again, and becomes a mechanism of circulation.

As shown in Fig. 3 and Fig. 4, the oil vapor generator 70 of the present example is inserted into the bottom of the casing 51 of the oil diffusion pump 50 shown in Fig. 2 through the plate-like gantry 70a. The gantry 70a is supported by the lower cover (flange) 90 from the atmosphere side. A heat insulating material (not shown) may be interposed between the gantry 70a and the lower cover 90. The lower cover 90 is detachably attached to the bottom surface of the casing 51 by a fastener 92 such as a bolt, and the atmosphere side of the bottom of the casing 51 is formed substantially flat.

Above the gantry 70a (upward direction of FIG. 3), a cylindrical case 71 as an example of the object to be heated is disposed. In the present example, the lower end thereof is supported by the base 72 having the opening portion 72a in the vicinity of the approximate center. The base plate 72 is supported by the gantry 70a through the foot 70b of a specific height, and is disposed so as to form a gap to the extent that the hydraulic oil 8 can pass between the pedestal 70a. In the present example, the gap between the base plate 72 formed by the foot portion 70b and the gantry 70a is used as a function of the preliminary heating flow path of the working oil. Further, by presenting this gap, the oil vapor generator 70 disposed in the casing 51 of the oil diffusion pump 50 is thermally insulated from the bottom surface of the casing 51.

Further, as the casing 71, a casing (not shown) integrally formed with the base 72 having the opening 72a and having a flange may be used. Further, the base plate 72 can be supported by the insulating plate member (not shown) of the induction coil 75, which will be described later, above the gantry 70a.

The casing 71 of the present example is composed of a material to be heated. As the material to be heated, at least one of stainless steel, carbon steel, and a rolled steel material for general structure defined in JIS-G3101 can be used.

As the stainless steel, for example, all kinds of SUS such as SUS304, SUS303, SUS302, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, and SUS302 can be used. The carbon steel system includes a low carbon steel such as a mild steel material, or a high carbon steel having a large carbon content such as a hard steel material. The rolled steel for general construction includes SS330, SS400, SS490, and SS540.

In particular, it is preferable to form the casing 71 by using a ferromagnetic material having a low electrical resistance such as a mild steel material having a specific resistance of from 10 × 10 ^-8 Ωm to about 20 × 10 ^-8 Ωm. In the case where the case 71 is formed using a ferromagnetic material (soft steel or the like) having a low electric resistance, the amount of eddy current generated by the induction coil 75 is increased due to the low resistance, and as a result, the case body 71 itself is passed. The amount of self-heating is also increased, and high efficiency can be expected.

Further, it is also preferable to form the casing 71 by using the SS400 having high availability of general steel materials. In this case, even if the object to be heated which is a high temperature is often immersed in the working oil in a vacuum environment, it is expected to exhibit rust resistance. Further, in addition to these, it is also possible to form the casing 71 using, for example, a molded article including a surface treatment material on the surface of the induction coil 75 on the side of the heating material.

In the present example, it is also possible to use the material to be heated to constitute the base 72 of the lower end of the support case 71.

The casing 71 includes a structure in which a peripheral wall thereof extends in an upright direction (up and down direction). The casing 71 constitutes an oil groove 59 (see FIG. 2) in two regions of the inner region 71a and the outer region 71b. Here, the hydraulic oil 8 is filled and accumulated. For example, in the case where the casing 71 is formed at a height of 120 mm, the water level of the oil surface L when the oil vapor generator 70 is stopped is about 30 mm. Fill the working oil 8. In this case, when the oil vapor generator 70 starts to operate, the oil level L of the hydraulic oil 8 is lowered by, for example, about 10 mm.

In the present example, in order to realize induction heating (low-frequency induction heating) as described later using low-frequency alternating current, the case 71 is preferably formed in a range of 5 mm to 12 mm in thickness.

Further, in the present example, the inner region 71a of the casing 71 is transmitted through the opening 72a of the base 72 to communicate with the outer region 71b of the casing 71 (see Fig. 3).

The induction coil 75 is wound around the outer circumference of the casing 71 through the insulating material 73. Thereby, the induction coil 75 is electrically insulated and disposed on the outer periphery of the casing 71 (an example in the vicinity). The insulating material 73 can be formed, for example, by using a polyimide film having a thickness of about 10 μm to 180 μm, a mica or a thermal spray of an insulating material on the outer surface of the object to be heated.

The wires constituting the induction coil 75 can be insulated and insulated with heat-resistant wires having a small electric resistance and a high heat-resistant temperature. Examples of such an object include an alumite-resistant electric wire obtained by subjecting an aluminum wire to an alumite treatment. The diameter of the wires constituting the induction coil 75 is preferably in the range of 2 mm to 4 mm. The number of layers of the induction coil 75 is preferably in the range of 7 to 14 layers.

The induction coil 75 is connected to a power supply device (not shown) for supplying power to the induction coil 75, and the power supply device controls the power supply state by a control device (not shown).

In the present example, since the casing 71 and the induction coil 75 are partially immersed in the arrangement of the hydraulic oil 8 together, the induction coil 75 is not abnormally heated to a temperature higher than the temperature of the hydraulic oil 8, Again, even When the temperature of the induction coil 75 itself rises, the cooling effect obtained by using the hydraulic oil 8 can also be expected. Further, the temperature rise of the induction coil 75 contributes to the heating of the working oil 8 and contributes to the energy saving effect.

Next, the operation of the oil vapor generator 70 will be described.

First, the power feeding device is actuated, and an alternating current is applied to the induction coil 75. The number of frequencies of the alternating current applied to the induction coil 75 is not particularly limited, and examples thereof include low frequency alternating current of several tens of Hz to several hundreds of Hz, but may be high frequency alternating current. Even if high frequency alternating current is supplied, the same effect can be obtained. Further, the control system of the power supply device uses the current control method, but may be the power control method. The following is a case where a low frequency alternating current is applied by a current control method.

When an alternating current having a commercial frequency of 50 Hz or 60 Hz is applied to the induction coil 75 by the operation of the power feeding device, a magnetic flux of a cross-link is generated in the upright direction of the casing 71, and a vortex is generated in the casing 71 by the magnetic flux. Current and Joule heat is generated. By using this heat, the casing 71 itself is heated, whereby the hydraulic oil 8 accumulated in the inner region 71a of the casing 71 is directly heated. The oil vapor rising from the oil surface in the casing 71 is further heated by contact with a high temperature portion of the upper portion of the casing 71 exposed above the oil surface, and is heated to a high temperature. It rises in the injector 53 and is ejected from the nozzle 53a.

As described above, since the casing 51 of the oil diffusion pump 50 is cooled by the water cooling pipe 58, the oil vapor of the working oil 8 adhering to the inner wall of the casing 51 is cooled and condensed, and is returned to the casing below the casing 51. The outer region 71b of the body 71 (synonymous with the oil groove 59 of Fig. 2). In this example, because of the inside of the casing 71 The side region 71a communicates with the outer region 71b of the casing 71 through the opening 72a of the base 72 (see Fig. 3). Therefore, the hydraulic oil 8 which has been condensed and returned is passed through the base formed by the foot 70b. 72 is gapped with the gantry 70a, and flows to the inner region 71a of the casing 71 through the opening 72a of the base 72, and is reheated by the oil vapor generator 70, and the working oil 8 is circulated by re-vaporization. .

Further, in the present example, in the case where the base 72 of the lower end of the support case 71 is formed of a material to be heated, the portion of the base 72 can be used as a heated body together with the case 71. In this case, the working oil 8 that is cooled in the casing 51 and can be returned to the outer region 71b of the casing 71 can be initially heated in the gap (i.e., the flow path) between the base 72 and the gantry 70a, and can be expected to be inside. The reheating of the region 71a contributes to an increase in the evaporation efficiency of the working oil 8.

In the case where the gantry 70a of the back support base 72 by the foot portion 70b is formed of a material to be heated similarly to the case 71 and the base 72, the gantry 70a can be expected to be used as the object to be heated.

In the oil vapor generator 70 of the present example, the heating source of the hydraulic oil 8 is used in the outer periphery of the cylindrical casing 71 formed of a material such as mild steel or SS400, and is passed through the insulating material 73. The induction coil 75 is wound, and the casing 71 is heated by applying low-frequency alternating current to the induction coil 75, and the working oil 8 is vaporized by the heat. Since the induction coil 75 is not heated, there is no problem of disconnection, and the heat generation function is not lost due to the disconnection, and the exhaust function of the oil diffusion pump 50 is not impaired. Moreover, there is no leakage due to poor insulation. Further, since the induction coil 75 itself does not become a heating element, it does not occur in the casing 51 and is deteriorated due to high temperature. The terminal block is in poor contact.

Further, in the case where the base 72 supporting the lower end of the casing 71 is also made of a material to be heated, by applying low-frequency alternating current to the induction coil 75, the base 72 can be heated and the efficiency of vaporization can be improved.

In the case where the gantry 70a of the back support base 72 is also made of a material to be heated, by applying low-frequency alternating current to the induction coil 75, the gantry 70a can be used as a heated body, and vaporization can be expected. effectiveness. In this case, by making the heat insulating material (not shown) interposed between the gantry 70a and the lower cover 90, the vaporization efficiency can be further improved.

Since the oil vapor generator 70 of the present example is incorporated in the oil diffusion pump 50 of the present example, the entire current flowing in the induction coil 75 of the oil vapor generator 70 can be caused by the casing 71 (or the casing 71 and the base plate). 72) consumed by itself. As a result, it is possible to contribute to shortening the heating and heating time of the hydraulic oil 8 (the activation time of the oil diffusion pump 50 can be shortened) by improving the energy efficiency and promoting the energy saving.

In the oil vapor generator 70 of the present example, the main portion (the casing 71, the insulator 73, and the induction coil 75) is placed in the state of being placed above the lower stage 70a, and is loaded into the casing 51. At the bottom, it is possible to form the atmosphere side of the bottom of the casing 51 substantially flat. As a result, it is also possible to provide the oil diffusion pump 50 which can be horizontally placed, and the convenience is improved.

In the oil vapor generator 70 of the present example, since the straight cubic upper end U of the casing 71 which is the heating element of the induction coil 75 is exposed above the oil surface L of the contact hydraulic oil 8, it is constituted. The oil vapor rising in the oil level L is transmitted through the upper portion of the casing 71 exposed above the oil level L. The oil vapor which is further heated by contact and which has been sufficiently heated is generated. As a result, in the oil diffusion pump 50 in which the oil vapor generator 70 of the present example is incorporated, it is possible to increase the temperature of the vapor ejected from the ejector 53, and it is very important to achieve an increase in the exhaust speed. benefit.

Further, the above examples are described in order to facilitate the understanding of the present invention, and are not intended to limit the present invention. Therefore, the respective elements disclosed in the above embodiments are intended to include all design changes and equivalents within the scope of the technology of the present invention.

For example, in the above-described example, the induction coil 75 is exposed to the outer peripheral portion of the induction coil 75 through the insulating material 73 on the outer periphery of the single-body casing 71 formed of a mild steel material, SS400 or the like (see the third section). Fig.), but is not limited by this aspect. For example, the casing 71 may be formed by a double layer structure of the inner wall of the casing and the outer wall of the casing, and may be, for example, the outer region 71b/the outer wall of the casing/the insulating material 73/the induction coil 75 The structure of the insulating material 73 / the inner wall of the casing / the inner region 71a is configured to achieve the effect of the present example.

According to this aspect, since the hydraulic oil 8 stored in the inner region 71a and the hydraulic oil 8 stored in the outer region 71b can be heated together, it is expected that the heating efficiency of the hydraulic oil 8 can be remarkably improved.

The tubular heating system is not limited to the illustrated sheet material, and in the configuration using the material to be heated, it may be a porous metal body and a mesh which can be wound by the working oil.

Further, in the above-described example, the outer peripheral side of the induction coil 75 is exposed (see FIG. 3). However, this aspect is not limited. For example, as shown in FIG. 5, the induction coil 75 can be substantially entirely (but Except for the lower part In addition, referring to Fig. 5), a magnetic shield case 76 formed of a material different from the material of the casing 71 is used. In such a manner, when the alternating current is applied to the induction coil 75 to heat the casing 71, it is expected that the heating efficiency can be further improved, which is a preferable aspect.

In the above-described example, the tubular body 71 is used as the object to be heated of the oil vapor generator 70. However, the plate member 71 such as a disk shape can be used without being limited thereto. As the object to be heated, a part or all of the entire plate material is immersed in the accumulated hydraulic oil 8 . In this case, the induction coil 75 can be disposed around the sheet material, for example, the back surface of the sheet material (the bottom side of the casing 51) through the insulating material 73. With this aspect, the effects of the present example can also be achieved.

Further, in the above-described example, one oil vapor generator 70 is provided in a single oil diffusion pump 50, but this is not limited to this aspect, and in particular, in the case of increasing the size of the oil diffusion pump, for example, the sixth As shown in Fig. 7 and Fig. 7, a plurality of oil vapor generators 70 of the present example can also be disposed at the bottom of the casing 51.

[Examples]

Next, examples (embodiments) and comparative examples of the present invention will be described.

[Examples]

In the present example, an oil vapor generator 70 (Fig. 3), which is a heating source for the working oil, is prepared by being loaded into the oil diffusion pump 50 (Fig. 2) shown below, and evaluated under the following conditions.

(oil diffusion pump 50)

. Diameter of the exhaust port: 250mm. Exhaust speed: 2900L/sec, The arrival pressure in the vacuum vessel: 6.7 × 10 ^-6 Pa (pascal) or less. The required power: 0.7KW,. Working oil: LION S, 1L.

(Oil vapour generator 70)

. The height of the box body 71 is 120 mm. Oil level L of working oil: 30mm (when stopped), 10mm (when operating).

[Comparative example]

In the present example, an oil diffusion pump of a conventional configuration in which an electrothermal heater is disposed at the bottom of the pump is prepared and evaluated under the following conditions, wherein the electrothermal heater utilizes a heating wire (nickel-chromium wire). As a working oil heating source.

(known oil diffusion pump)

. Diameter of the exhaust port: 250mm. Exhaust speed: 2900L/sec, The arrival pressure in the vacuum container: 6.7 × 10 ^-6 pa (Pascal) or less. The required power: 2.0KW (200V),. Working oil: LION S, 1L.

[Evaluation]

The measurement of the operating power was performed using the oil diffusion pump of each example. Specifically, the power supply portion of the nichrome wire (comparative example) and the induction coil (example) is measured using a clamp-type electric meter, and electric power is calculated from voltage, current, and power factors (power at startup, power during operation) ), and the ratio of the examples to the comparative examples (conventional ratio) was calculated. As a result, the operating electric power of the embodiment was reduced by 40% at the time of starting, and the conventional ratio at the time of operation was reduced by 65%, and it was found that the electric power can be greatly reduced at the time of starting and running.

The temperature (side, bottom) of the oil diffusion pump of each example was measured. As a result, the side temperature (atmosphere side) of the examples was 170 °C. This is a 26% reduction compared to the comparative example (230 ° C), and it can be confirmed that the heating can be concentrated in the boiler inner cylinder and contributes to the reduction of electric power. Further, the bottom surface temperature of the examples was 120 °C. This is compared with the comparative example (hot state) in which the hot heater component is exposed and is very high in temperature, and it can be found that heat loss can be greatly suppressed. Moreover, even if the floor damage is not considered, it can be found that a good level can be achieved.

8‧‧‧Working oil

51‧‧‧Shell

70‧‧‧Oil vapour generator

70a‧‧‧Rack

70b‧‧‧foot

71‧‧‧Box

71a‧‧‧Inside area

71b‧‧‧Outer area

72‧‧‧Base

72a‧‧‧ openings

73‧‧‧Insulation materials

75‧‧‧Induction coil

90‧‧‧Under cover (flange)

92‧‧‧fasteners

L‧‧‧ oil noodles

U‧‧‧ Straight cube up

Claims (9)

An oil diffusion pump is provided with an oil vapor generator disposed in an ejector disposed in a casing, and the working oil is heated to become oil vapor by actuating the oil vapor generator, and the oil in the ejector is The steam is ejected from the ejector to perform a high-vacuum venting operation of the suction gas, wherein the oil vapor generator includes a heated body, and the induction coil is electrically insulated from being disposed in the vicinity of the object to be heated; The power feeding device applies an alternating current to the induction coil; the heated body and the induction coil are placed in the housing in a position in which a part or all of the working oil accumulated in the housing is immersed; The device is actuated to heat the heated body and to vaporize the working oil. The oil diffusion pump according to claim 1, wherein the heated system of the oil vapor generator is a cylindrical shape extending in an upright direction, and the induction coil is wound around the cylindrical material through an insulating material. The circumference of the body to be heated. The oil diffusion pump according to claim 1, wherein the heated system of the oil vapor generator has a plate shape, and the induction coil is disposed around the plate-shaped object to be heated through an insulating material. An oil diffusion pump according to any one of claims 1 to 3, wherein a working oil flow path is provided in the casing. An oil diffusion pump according to any one of claims 1 to 4, wherein there is no heat source at the bottom of the atmosphere side casing. An oil diffusion pump according to any one of claims 1 to 5, wherein the oil vapor generator disposed in the casing is thermally insulated from the bottom surface of the casing. The oil diffusion pump according to any one of claims 1 to 6, wherein the induction coil is composed of an insulated and heat-resistant electric wire. A vacuum apparatus is provided with an exhaust device for evacuating a vacuum vessel, and the oil diffusion pump according to any one of claims 1 to 7 is used as the exhaust device. An oil vapor generator that heats hydraulic oil in an oil diffusion pump including a casing and an ejector into oil vapor, which is used by being mounted in the casing in the oil diffusion pump, and The oil vapor generator includes: a heated body to be disposed in the injector in such a manner that a part or all of the working oil is immersed in the casing; the induction coil is to be partially or completely impregnated The working oil accumulated in the casing is electrically insulated from being disposed in the vicinity of the object to be heated; and the power feeding device applies alternating current to the induction coil; and the heating device is activated to activate the heater The body is heated and the aforementioned working oil is vaporized.